Rashi on Exodus 31:14/רש"י על שמות ל״א:י״ד

1מות יומת SHALL SURELY BE PUT TO DEATH by the judges if there are witnesses testifying to the desecration and if the warning required by law had been given to the culprit immediately before he committed the offence.

2ונכרתה SHALL BE CUT OFF [FROM AMONG HIS PEOPLE] by God, if no such warning had been given (Mekhilta).

3מחלליה means, whosoever treats it as חול, ordinary, in so far as its sanctity is concerned.